nick_thames

Im putting 3:73's in this afternoon to run a guy at the track this weekend. I wanted to know whats the best kind of rear gear oil to use witht he swap. I will probably switch them out for 4:10's or 4:30's later but i already had a new set and wanted to put them in just to see. any help would be greatly appreciated.

sstang

Royal Purple is a common choice. Any 75w90 oil will work, but friction modifier is suggested with most.

nick_thames

thanks. ive heard that royal purple has friction modifier in it but do i need some anyway?

Colorado_Mustang

I know Amsoil gear lube doesn't need the friction modifier, I would assume the other high end synthetics would be the same.

The gears you bought should tell you the weight to run. My Richmonds called for 75w140.